Does voltage matter for an ammeter to work?

"John G" > wrote in message
...
>
> > wrote in message
> ups.com...
>> The loop was likely a piece of metal that had a calibrated
>> resistance,
>> across which the ammeter movement was connected to measure the
>> voltage
>> drop created by the resistance. This is most common in automotive
>> ammeters. The loop is the "shunt."
>>
>> Dan
>
>
> No.. The loop was a coil (one turn often) which created a magnetic
> field which moved the iron vane attached to the pointer. Very simple,
> very cheep but worked.
>
> Why would you try to generate a voltage to drive a voltmeter which
> after all is only a high resistance amp meter, when the simple amp
> meter is so much cheaper, and inserts less voltage drop in the circuit
> than any shunt.
> --
And I forgot to add above.

The insulation of Automotive ampmeters is not good enough to use them in
Mains voltage circuits.
Theoretically the voltage is of no consequence but auto amp meters are
only safe for automtive voltages.
--
John G

Wot's Your Real Problem?

yep.
sam

"Masospaghetti" > wrote in message
...
> More specifically, would a 12-volt ammeter work with a 6-volt system?

"Scotty" > wrote in message
oups.com...
> A volt meter measures voltage and an ammeter measures current. In doing
> measurements, they are independent. Therefore, your ammeter is not
> voltage-dependent. There's no such thing as a 12-volt ammeter or a
> 6-volt ammeter. An ammeter will work regardless of the voltage in the
> system. Just mind your polarities and make sure that your test leads
> are large enough to handle the maximum current you intend to measure.
>
> Regards,
> scotty
>
Plus, make sure any ammeter has a scale large enough to handle the amps
it is to measure. Theoretically, a 6-volt blower motor with .25 hp will
draw twice the amps of a 12-volt motor with .25 hp. Reckon that has
something to do with newer aftermarket gauge systems using voltmeters rather
than ammeters--plus cost to mfg. higher-amp ammeters may be more than these
voltmeters: they certainly shouldn't get so hot! s

>No.. The loop was a coil (one turn often) which created a magnetic
field
>which moved the iron vane attached to the pointer. Very simple, very
>cheep but worked.

A new one on me. The vane must have been magnetic so it would
respond to forward and reverse flows. Simple and effective.

>Why would you try to generate a voltage to drive a voltmeter which
after
>all is only a high resistance amp meter, when the simple amp meter is
so
>much cheaper, and inserts less voltage drop in the circuit than any
>shunt.

Because the d'Arsonval movement used in microammeters is so common and
easy to convert to an ammeter with a shunt. I've built them using steel
welding rod for a shunt for higher currents, and stainless wire for
smaller currents. Auto manufacturers are still using this system,
though I suppose it's digital in many cases now. The shunt can be
located at a distance from the meter movement so that you don't have
honkin' great wires leading from the power system to the meter on the
panel and back to the loads. Saves on the wire, makes things more
compact, and reduces chance of fire under the panel.

Dan